The city, which has been experimenting with several green technologies and trying to encourage green companies to locate there, will evaluate the cost-effectiveness of replacing 250-watt high pressure sodium "Cobra-head" street lights with LED street lights, which consume far less energy. The city estimates it could save up to $500,000 a year in utility bills by inserting LEDs in 5,000 street lights alone.

Maintenance costs would also likely decline because LEDs last longer. Although LEDs cost more, advocates say that the total cost of ownership, particularly in public light figures, is lower.

The LED city program is being driven by--surprise, surprise--LED manufacturer Cree. The company has kicked off projects with Raleigh, N.C.; Toronto; and Ann Arbor, Mich. Raleigh, for instance, retrofitted a public parking garage with LEDs and now wants to expand to its other parking garages.

Last December, Austin inserted LED lighting into a parking garage. The city estimates that it will save $10,178 in utility and maintenance costs a year. Payback for the lights could come in 6.5 years, the city said. (In 2003, the city replaced 5,200 traffic signals and 3,700 pedestrian signals with LED fixtures.)

The public sector isn't the only one buying LED lights. AgiLight and LED Lighting Fixtures, which make LED fixtures, say they are seeing a growing business in replacing neon signs in Las Vegas and other cities with LED lookalikes. Restaurants and stores are also experimenting with LED fixtures.